Fig. Xa. Lateral view of the egg represented in Fig. X. The 

 spiracles (Sp) have become contracted to minute circular aper- 

 tures; the stomodaeum (Sto), proctodaeum (Pro), and the 

 Malpighian tubules (Mai) are now evident. 



Fig. XI. Ventral view. The silk glands (SlkGl) now reach 

 into the posterior segments of the abdomen, the rudiments of 

 the tracheal commissures (TraCom) of each are about to unite 

 on the ventral mid-line. 



Fig. XII. Ventral view. Estimated at 58-60 hours. The 

 tracheal commissures (TraCom) are completed, the second 

 maxillae (2M.Y) are beginning to approach one another, and the 

 ventral nerve cord ( VNC) is visible from the surface. 



